The Schengen agreement on open borders was “temporarily suspended” in Austria Saturday as Chancellor Werner Faymann added his voice to a chorus of leaders warning that the refugee crisis threatened to pull the EU apart.

The failure of the EU to reach agreement on a fair allocation of refugees and to secure its external borders threatens not just Schengen but the European project as a whole, he said in an interview for Austria’s Österreich newspaper.

“It is extremely troubling that the EU’s complicated structures have prevented it from resolving important issues like the avalanche of refugees or the financial crisis more quickly. Every time the risk is that it is doing too little, too late,” he said.

Vienna’s move comes as Germany has begun sending hundreds of refugees back over the Austrian border ever day. Austria has already begun implementing stricter checks on its southern border with Slovenia. Refugees have to present a valid identity card and those who do not have a right to asylum, plan to travel to Scandinavia, or have been already rejected by Germany, will be denied entry.

“Anyone who arrives at our border is subject to control,” Faymann said.

The new regulations came into force Saturday. More than 3,000 migrants arriving under false identities have already been sent back since the beginning of the year, border officials reported.

“If the EU does not manage to secure the external borders, Schengen as a whole is put into question … Then each country must control its national borders,” Faymann told the newspaper, adding that if the bloc’s external borders are not secured in the near future, “the whole EU [will be] in question.”

Earlier this week, other Schengen countries, including Norway, Sweden and Denmark, also temporarily suspended the Schengen agreement and restored border control measures at their national borders.